KR102535495B1 - Oil-in-water emulsified sunblock cosmetic - Google Patents

Abstract

An object of the present invention is to provide an oil-in-water emulsified sunscreen cosmetic that maintains a high UV protection effect even when in contact with water or sweat after application and has an excellent touch. The present invention contains (A) a sunscreen agent and (B) a fatty acid that is solid at room temperature, and the neutralization rate of the fatty acid is 51% or less, (A) sunscreen agent and (B) the blending ratio of the fatty acid ((( A) / (B)) relates to an oil-in-water emulsified sunscreen cosmetic, characterized in that within the range of 0.1 or more and less than 10.0. The cosmetic material exhibits an unprecedented characteristic that the ultraviolet ray protection ability is improved by contacting with water. It is preferable that the cosmetics further contain an oil component having (C)IOB of 0.5 or more.

Description

Oil-in-water emulsified sunscreen cosmetics {OIL-IN-WATER EMULSIFIED SUNBLOCK COSMETIC}

The present invention relates to an oil-in-water emulsified sunscreen cosmetic. More specifically, it relates to an oil-in-water emulsified sunscreen cosmetic having an unprecedented property that the ultraviolet protection effect is improved than immediately after application by contact with water or sweat.

Protecting the skin from the harm of ultraviolet rays is one of the important tasks in skin care and body care, and various UV care cosmetics have been developed to minimize the adverse effects of ultraviolet rays on the skin. Sunscreen cosmetics (sunscreen cosmetics), a type of UV care cosmetic, protects the skin from the harm of ultraviolet rays by blocking UVA and UVB from reaching the skin by blending an ultraviolet absorber or an ultraviolet scattering agent (Non-Patent Document 1). In recent years, it is considered important to protect the skin from ultraviolet rays in everyday life, not limited to harsh ultraviolet conditions in outdoor activities such as swimming in a pool or sea in summer or skiing in winter, It is also desired to have an ultraviolet ray protection effect.

As formulations of sunscreen cosmetics, formulations in the form of emulsions are often used, and the instability of emulsions sometimes causes a decrease in the ability to block ultraviolet rays. In Patent Literature 1, it is described that storage stability is improved by blending a free fatty acid having 14 to 24 carbon atoms, and the decrease in ultraviolet protection ability due to long-term storage is suppressed.

However, even if the UV protection ability is maintained until immediately before use, when the sunscreen cosmetics applied to the skin come into contact with water or sweat, the UV absorber or the UV scattering agent leaks out of the applied cosmetics, and the UV protection effect is reduced. . Therefore, various attempts have been made, such as improving the water resistance or film strength of sunscreen cosmetics, in order to prevent the outflow of the sunscreen.

For example, in Patent Document 2, a water-swellable clay mineral, a quaternary ammonium salt-type cationic surfactant, a polyoxyalkylene-modified organopolysiloxane, an aqueous phase, and an organic compound represented by the general formula R _n SiO _(4-n)/2 A water-in-oil emulsion composition containing a silicone resin is disclosed, and it is proposed to improve water resistance and water repellency by blending an organic silicone resin, and to keep an ultraviolet absorber on the skin for a long time.

In addition, Patent Document 3 discloses a water-in-oil emulsified cosmetic containing a UV inhibitor, an organic modified clay mineral, a volatile component, a spherical resin powder, and a coating agent. It is proposed to prevent

In addition, oil-in-water emulsions are widely used as sunscreen cosmetics because they provide a glossy texture. However, oil-in-water emulsified cosmetics are often inferior to water-in-oil types in water resistance, and the ultraviolet ray blocking ability is easily deteriorated due to leakage of ultraviolet absorbers and ultraviolet scattering agents. Therefore, an attempt has been made to improve the water resistance by also blending a coating agent (Patent Document 4) or to enhance the ultraviolet ray protection effect by blending a high amount of a UV absorber (Patent Document 5).

However, cosmetics applied to the skin are exposed to various moisture from inside and outside the coating film, such as sweat secreted from the skin and moisture from the external environment such as seawater. It was difficult to completely stop the outflow of the ritual. In addition, it was considered that even when the outflow of the ultraviolet absorber or the like can be completely prevented, the obtained ultraviolet protection effect will not exceed that immediately after application.

In addition, if a high amount of silicone resin or film agent is used, the film feeling of the applied cosmetic material becomes stronger and the usability is impaired, and the application is poor, so it cannot be easily removed with normal detergent or soap, and the UV protection effect requires the use of a dedicated cleansing agent. In some cases, a separate problem arises.

Japanese Unexamined Patent Publication No. 2015-30723 Japanese Unexamined Patent Publication No. 1-180237 Japanese Unexamined Patent Publication No. 8-217619 Japanese Unexamined Patent Publication No. 2004-91377 Japanese Unexamined Patent Publication No. 2012-140404

「New Cosmetics」 2nd edition, edited by Takeo Mitsui, 2001, published by Nanzando, pages 497-504

The present invention is based on the discovery that, in the course of research to develop a sunscreen cosmetic with a strong ultraviolet protection effect, the ultraviolet protection effect is not lowered by contact with water or sweat, but on the contrary, the effect is improved. It is an object of the present invention to provide a sunscreen cosmetic having an innovative property that is not conventionally improved by improving the ultraviolet protection effect.

As a result of repeated intensive studies to solve the above problems, the inventors of the present invention have found that by blending an ultraviolet absorber and/or an ultraviolet scattering agent with a fatty acid, and setting the neutralization rate of the fatty acid to a predetermined value or less, the novel properties aimed at are obtained. The present invention was completed by discovering that a sunscreen cosmetic could be obtained.

That is, the present invention provides an oil-in-water emulsified sunscreen cosmetic that contains (A) a sunscreen agent and (B) a fatty acid that is solid at room temperature and has a neutralization rate of 51% or less of the fatty acid.

In the present invention, by adopting the above configuration, the UV protection effect after contact with water, sweat, etc. is remarkably improved compared to immediately after application of the cosmetic to the skin. That is, the oil-in-water emulsified sunscreen cosmetics according to the present invention have innovative ultraviolet rays properties that are opposite to the conventional common sense that the ultraviolet rays protection effect is improved by contact with moisture, which has been the cause of deterioration in conventional sunscreen cosmetics. It is a blocking cosmetic.

In addition, the sunscreen cosmetic of the present invention has no film feeling and is easy to apply when applied because it exhibits an excellent ultraviolet protection effect even without a high amount of silicone resin or film agent to improve water resistance. In addition, the oil-in-water emulsified cosmetics maintain the original characteristics, and not only impart a glossy feel when applied, but also have excellent usability without stickiness or shine, and can be easily erased with ordinary detergents or soaps.

1 is a photomicrograph showing a cross-section of a cosmetic coating film immediately after applying the cosmetic composition of Example 19 to a simulated skin substrate (PMMA substrate with irregularities) and after bathing in water for 30 minutes. 1(a) and 1(b) show cross-sections of the coating film immediately after application to the skin ridge portion, and FIGS. 1(d) and 1(e) show cross-sections of the coating film after bathing in water. Fig. 1 (c) shows a cross section of the coating film immediately after application to the skin groove, and Fig. 1 (f) shows a cross section of the coating film after bathing in water. It is shown that the thickness of the non-uniform film at the time of application becomes uniform after bathing in water.

The action mechanism by which the sunscreen cosmetic of the present invention exhibits the unique property of improving the ultraviolet protection effect by contacting with water is not necessarily elucidated at present, but it can be considered as follows.

First of all, it is considered that there is non-uniformity in the coating film containing the ultraviolet protection agent immediately after applying the sunscreen cosmetic of the present invention having the above structure to the skin. However, when this coating film comes into contact with moisture such as tap water, seawater, sweat, etc., minerals such as calcium ions and magnesium ions contained in these moisture interact with fatty acid components, resulting in increased water repellency of the coating film compared to the state immediately after application. uniformity is improved. It is known that the uniformity of the coating film of the sunscreen cosmetic is important to the ultraviolet protection effect, and in this way, a higher ultraviolet protection effect than immediately after application is realized, and deterioration of the ultraviolet protection ability due to leakage of the ultraviolet protection agent is prevented.

In fact, observation with an electron microscope or the like confirmed that the uniformity (density of the surface and homogeneity of the film itself) of the coating film after contact with moisture was improved compared to immediately after application of the sunscreen cosmetic of the present invention. Conversely, in conventional sunscreen cosmetics, the uniformity of the film deteriorates upon contact with moisture. According to what the present inventors have confirmed, even in the case of a coating film formed from a sunscreen cosmetic of the same composition, a uniform coating film as a whole has significantly better UV protection ability than a non-uniform coating film. This is considered to be because the ultraviolet ray blocking ability does not increase additively with an increase in film thickness, but increases synergistically in proportion to the film thickness.

Next, each component constituting the sunscreen cosmetic of the present invention will be described in detail.

<(A) UV protection agent>

(A) UV protection agent (hereinafter sometimes simply referred to as "(A) component") formulated in the water-in-water emulsified sunscreen cosmetic according to the present invention means a UV absorber and/or a UV scattering agent, and What is usually blended with cosmetics can be used.

The ultraviolet absorber used in the present invention is not particularly limited, but specific examples include ethylhexyl methoxysuccinate, octocrylene, dimethicodiethylbenzalmalonate, polysilicon-15, t-butylmethoxydibenzoylmethane, and ethylhexyltria. Zone, diethylaminohydroxybenzoylbenzoate hexyl, bisethylhexyloxyphenolmethoxyphenyltriazine, oxybenzone-3, methylenebisbenztriazolyltetramethylbutylphenol, phenylbenzimidazolesulfonic acid, homosalate, ethylhexyl salicylate Organic ultraviolet absorbers, such as these, are mentioned.

Although the ultraviolet scattering agent used in the present invention is not particularly limited, specific examples thereof include particulate metal oxides such as zinc oxide, titanium oxide, iron oxide, cerium oxide, and tungsten oxide.

The UV scattering agent may be one without surface treatment or one with various types of surface treatment. As the surface treatment agent, those generally used in the cosmetic field, for example, alkoxysilanes such as octyltriethoxysilane, dextrin palmitate, etc. Fatty acids such as dextrin fatty acid ester and stearic acid can be used.

The blending amount of component (A) is preferably 5% by mass or more, more preferably 5 to 40% by mass, still more preferably 6 to 20% by mass, based on the total amount of the oil-in-water emulsified sunscreen cosmetic. If the blending amount of component (A) is less than 5% by mass, it is difficult to obtain sufficient ultraviolet protection effect, and even if blending exceeds 40% by mass, an increase in the ultraviolet protection effect suitable for the blending amount cannot be expected, and stability and usability tend to deteriorate. .

Further, the ultraviolet protection agent (component (A)) of the present invention includes an embodiment comprising only an ultraviolet absorber, an embodiment comprising only an ultraviolet scattering agent, and an embodiment containing both an ultraviolet absorber and an ultraviolet scattering agent.

<(B) fatty acid>

The (B) fatty acid (hereinafter sometimes simply referred to as "(B) component") used in the present invention is not particularly limited as long as it can be used in cosmetics, etc., and contains a linear or branched chain saturated or unsaturated hydrocarbon group. It can be selected from fatty acids having

In particular, it is a solid at room temperature, and also includes a linear higher fatty acid having 8 to 22 carbon atoms, such as lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid (behenic acid), oleic acid, and the like. can Among them, it is particularly preferable to use one or two or more selected from stearic acid, palmitic acid and behenic acid.

In addition, the fatty acids used in the present invention are partially neutralized (neutralization rate is 51% or less) by counter ions (cations).

In the present specification, "neutralization rate (of fatty acids)" refers to the total number of equivalents of fatty acids blended in oil-in-water emulsified cosmetics as "Ea'" and the total number of equivalents of substances excluding fatty acids from acidic substances in cosmetics as "Ea"" , Defined as a numerical value represented by the following formula (A) when the total number of equivalents of basic substances blended in cosmetics is set to "Eb".

[(Eb-Ea")/(Ea')]×100(%) (A)

In the cosmetic composition of the present invention, the basic material used as a neutralizing agent for the fatty acid (component (B)) is a material capable of supplying counter ions (cations) that neutralize fatty acid anions, and may include inorganic bases, organic bases, Any cationic polymer or the like may be used, and it is not particularly limited.

Representative examples of the inorganic base include sodium hydroxide, potassium hydroxide, and ammonium chloride.

Examples of organic bases include amines such as monoethanolamine, diethanolamine, triethanolamine, aminomethylpropanediol, 2-amino-2-methylpropanol (AMP), triisopropanolamine (TIPA), tris[(2-hydroxy Basics such as )-1-propyl]amine, 2-amino-2-methyl-1,3-propanediol (AMPD) and 2-amino-2-hydroxymethyl-1,3-propanediol, N-methylglucamine amino acids such as arginine and lysine.

The cationic polymer may be a cationic polymer that can be used in cosmetics or skin external preparations, and is not particularly limited. As specific examples, cationized cellulose derivatives [for example, quaternary nitrogen-containing cellulose ethers (“Polymer JR-400”, “Polymer JR-125”, “Polymer JR-300M” (all manufactured by Union Carbide Corporation), etc.)], Cationized guar gum, cationized locust bean gum, cationized tara gum, diallyl quaternary ammonium salt homopolymer, diallyl quaternary ammonium salt/acrylamide copolymer [for example, dimethyldiallylammonium chloride/acrylamide copolymer ( "Makoto 2200", manufactured by naruco.co., ltd., etc.], quaternized polyvinylpyrrolidone derivatives, polyglycol polyamine condensates, vinylimidazolium trichloride-vinylpyrrolidone copolymers, hydroxyethyl cellulose Dimethyldiallylammonium chloride copolymer, vinylpyrrolidone-quaternized dimethylaminoethyl methacrylate copolymer, polyvinylpyrrolidone-alkylaminoacrylate copolymer, polyvinylpyrrolidone-alkylaminoacrylate-vinyl Caprolactam copolymer, vinylpyrrolidone/methacrylamidepropyltrimethylammonium chloride copolymer, alkylacrylamide/acrylate/alkylaminoalkylacrylamide/polyethylene glycol methacrylate copolymer, adipic acid/dimethylaminohydroxypropyl Ethylenetriamine copolymer, vinylpyrrolidone/N,N-dimethylaminoethyl methacrylate/stearyl acrylate/tripropylene glycol diacrylate copolymer ("CG Polymer (D)", manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.), etc. ] and the like. However, it is not limited to these examples.

In the present invention, by setting the neutralization rate of fatty acid to 51% or less, it is possible to obtain an unprecedented characteristic that the UV protection effect is improved by contact with water. The "fatty acid having a neutralization rate of 51% or less" includes unneutralized fatty acids and fatty acids having a neutralization rate of 51% or less calculated according to the above formula (A). Expressed as a numerical range, the neutralization rate of fatty acids in the present invention is 0 to 51%, and all numerical values included in this range, for example, 0.001, 0.01, 0.1, 0.5, 1, 5, 10, 15, 20, 25 , 30, 35, 40, 45, or 50%, or any numerical range with these values as the lower limit or upper limit can be employed.

The compounding amount of component (B) in the cosmetic composition of the present invention may satisfy the requirements of the following compounding ratio based on the compounding quantity of the ultraviolet ray protection agent to be formulated together, and is usually blended in the range of about 1% by mass to 40% by mass. . It is preferably more than 5% by mass and a blending amount of 40% by mass or less. Needless to say, this blending amount range can take all the values within the above range. Here, "more than 5% by mass" is the lower limit of the compounding amount, but does not include 5% by mass, but a compounding amount larger than that, for example, 5.1% by mass or more, 5.5% by mass or more, 6% by mass or more, 7% by mass or more, It means that it is 8 mass % or more, 9 mass % or more, or 10 mass % or more. On the other hand, the upper limit of the compounding amount can be set to 40 mass% or less, 35 mass% or less, 30 mass% or less, 28 mass% or less, 25 mass% or less, 22 mass% or less, or 20 mass% or less.

On the other hand, the amount of the basic substance (neutralizing agent) to be blended to neutralize the fatty acid is based on the formula (A) so that the neutralization rate of the fatty acid is 51% or less from the blending amount of the fatty acid and the blending amount of other acidic materials. Can be calculated there is.

In order to reliably exhibit the desired effect in the cosmetic composition of the present invention, the blending ratio ((A)/(B)) of the ultraviolet absorber and/or ultraviolet scattering agent (component (A)) and the component (B) is 0.1 or more and 10.0 It is necessary to do less than When this ratio is 10.0 or more, the effect peculiar to this invention that an ultraviolet-ray protection effect improves when it contacts with water|moisture content may not be acquired. Of course, less than 10.0 is a concept that does not include 10.0 but includes all values smaller than that. This compounding amount ratio can take all numerical values and all numerical ranges (eg, 0.1 to 9.0, 0.2 to 8.0, or 0.3 to 7.0) included in 0.1 or more and less than 10.0. That is, the upper limit of the blending ratio may be set to 9.9, 9.8, 9.7, 9.6, 9.5, 9.0, 8.0, 7.0, or 6.0, and the lower limit may be set to 0.1, 0.15, 0.2, 0.3, or 0.4.

<(C)IOB of 0.5 or more>

In the water-in-water emulsified sunscreen cosmetic of the present invention, in addition to the above essential components, (C) IOB of 0.5 or more oil is further blended to increase the ultraviolet protection ability before contact with moisture (hereinafter, the initial ultraviolet protection ability), and also before and after bathing in water. It is possible to further increase the extent and rate of improvement of the UV defense ability of

The IOB value is the ratio (Inorganic Organic Balance) of the inorganic value (IV) to the organic value (OV) in the organic conceptual diagram, and refers to "inorganic value (IV)/organic value (OV)". The concept organic diagram assumes that methane (CH ₄ ) is the source of all organic compounds, and all other compounds are regarded as derivatives of methane. The organic value and the inorganic value are obtained, and the organic value is plotted on the X-axis and the inorganic value on the Y-axis. reference).

As the oil component with (C)IOB of 0.5 or more used in the present invention (hereinafter sometimes simply referred to as "(C) component"), ester oils such as diethoxyethyl succinate, alkylene polyglycol dineopentanoate, Alkylene oxide derivatives containing polyalkylene glycols such as polyethylene glycol (PEG), polypropylene glycol (PPG) and polybutylene glycol (PBG), etc., which have been conventionally used in cosmetics are preferable.

In this invention, it is especially preferable to use an alkylene oxide derivative, especially a random type alkylene oxide derivative represented by the following formula (I).

R ¹ O-[(AO) _m (EO) _n ]-R ² (I)

[Wherein, AO is an oxyalkylene group having 3 to 4 carbon atoms, EO is an oxyethylene group, m and n are the average added mole numbers of the oxyalkylene group and oxyethylene group, respectively, 1≤m≤70, 1≤n≤70 am. The ratio of the oxyethylene group to the total of the oxyalkylene group having 3 to 4 carbon atoms and the oxyethylene group is 20 to 80% by mass. The oxyalkylene group having 3 to 4 carbon atoms and the oxyethylene group may be added in a block shape or in a random shape. R ¹ and R ² are hydrocarbon groups having 1 to 4 carbon atoms or hydrogen atoms, which may be the same or different, and the ratio of the number of hydrogen atoms to the number of hydrocarbon groups in R ¹ and R ² is 0.15 or less.]

In the alkylene oxide derivative of formula (I), AO is an oxyalkylene group having 3 to 4 carbon atoms, specifically an oxypropylene group, an oxybutylene group, an oxyisobutylene group, an oxytrimethylene group, an oxytetramethylene group, etc. can be heard Preferably, an oxypropylene group and an oxybutylene group are used. EO is an oxyethylene group. m is the average number of added moles of an oxyalkylene group having 3 to 4 carbon atoms, and is 1≤m≤70, preferably 2≤m≤50. n is the average added mole number of oxyethylene groups, and is 1≤n≤70, preferably 5≤n≤55.

Moreover, it is preferable that the ratio of the oxyethylene group with respect to the total of the oxyalkylene group of 3-4 carbon atoms and the oxyethylene group is 20-80 mass %. The order of addition of ethylene oxide and an alkylene oxide having 3 to 4 carbon atoms is not particularly specified. Further, the oxyethylene group and the oxyalkylene group having 3 to 4 carbon atoms may be added in a block shape or may be added in a random shape. Preferably, what is added in a random shape is mentioned.

R ¹ and R ² are hydrocarbon groups having 1 to 4 carbon atoms or hydrogen atoms, and hydrocarbon groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl and the like. An alkyl group is mentioned. Preferably they are a methyl group and an ethyl group. In a hydrocarbon group having 5 or more carbon atoms, the effect of the present invention tends to decrease. R ¹ and R ² may be the same or different.

As for R ¹ and R ² , each one type may be used, or a hydrocarbon group having 1 to 4 carbon atoms may be mixed, or a hydrocarbon group having 1 to 4 carbon atoms may be mixed. However, as for the proportion of hydrocarbon groups and hydrogen atoms among the hydrocarbon groups of R ¹ and R ² , the ratio Y/X of the number of hydrogen atoms (Y) to the number (X) of hydrocarbon groups is 0.15 or less, preferably 0.06 or less. .

The alkylene oxide derivative of formula (I) can be manufactured by a known method. For example, after addition polymerization of ethylene oxide and an alkylene oxide having 3 to 4 carbon atoms to a compound having a hydroxyl group, it is obtained by subjecting an alkyl halide to an ether reaction in the presence of an alkali catalyst.

Specific examples of the alkylene oxide derivative of formula (I) include POE (9) POP (2) dimethyl ether, POE (14) POP (7) dimethyl ether, POE (10) POP (10) dimethyl ether, POE (6) POP (14) dimethyl ether, POE (15) POP (5) dimethyl ether, POE (25) POP (25) dimethyl ether, POE (7) POP (12) dimethyl ether, POE (22) POP (40) dimethyl ether, POE (35) POP (40) dimethyl ether, POE (50) POP (40) dimethyl ether, POE (55) POP (30) dimethyl ether, POE (30) POP (34) dimethyl ether, POE (25) POP ( 30) dimethyl ether, POE (27) POP (14) dimethyl ether, POE (55) POP (28) dimethyl ether, POE (36) POP (41) dimethyl ether, POE (7) POP (12) dimethyl ether, POE (17) POP (4) dimethyl ether, POE (9) POB (2) dimethyl ether, POE (14) POB (7) dimethyl ether, POE (10) POP (10) diethyl ether, POE (10) POP ( 10) Dipropyl ether, POE (10) POP (10) dibutyl ether, etc. are mentioned. In the present invention, polyoxyethylene (POE)/polyoxypropylene (POP) dimethyl ether is preferably used, but is not limited thereto.

In addition, POE, POP, and POB are abbreviations of polyoxyethylene, polyoxypropylene, and polyoxybutylene, respectively.

Alkylene oxide derivatives in the present invention include polyalkylene glycols such as polyethylene glycol (PEG), polypropylene glycol (PPG) and polybutylene glycol (PBG).

The polyalkylene glycol in the present invention includes polyoxybutylene polyoxypropylene glycol such as polyoxybutylene (9) polyoxypropylene (1) glycol, polyoxyethylene polyoxypropylene glycol, etc. It is appropriately selected from the point of being usable for skin external preparations, but a molecular weight of 300 or more is preferable, and a molecular weight of 1000 or more is more preferable. The upper limit of the molecular weight is not particularly limited, but, for example, a molecular weight of 20000 or less, 5000 or less, or 2500 or less is suitably used.

Alkylene oxide derivatives in the present invention can be used by selecting one type or two or more types arbitrarily. 14) Polyoxypropylene (7) What contains dimethyl ether is especially preferable.

The upper limit of the IOB value of component (C) in the cosmetic composition of the present invention is not particularly limited, but, for example, an oil having IOB = 3.0 or less is preferably used.

(C) In the case of blending the component, the blending amount is not particularly limited, but, for example, by blending in the range of 0.005 to 20% by mass, 0.5 to 10% by mass, or 0.1 to 5% by mass, the ultraviolet ray protection ability after contact with moisture The time until the improvement effect is exerted is shortened.

The water-in-water emulsified sunscreen cosmetic of the present invention includes ingredients commonly used in cosmetics in addition to the above essential ingredients, such as moisturizers, thickeners, powders, alcohols, natural polymers, synthetic polymers, sugars, antioxidants, buffers, various extracts, and stabilizers. , preservatives, pigments, flavors, etc. can be appropriately incorporated within a range not impairing the effects of the present invention.

However, if the surfactant is blended in excess of 5.0% by mass, the coating film itself may flow when in contact with water, so it is preferable that the blending amount of the surfactant be 5.0% by mass or less, and the present invention Embodiments not included are also included.

The method for producing the oil-in-water emulsified sunscreen cosmetic of the present invention is not particularly limited. For example, it can be prepared by mixing the components constituting the oil phase and the components constituting the aqueous phase, adding the oil phase to the aqueous phase, and emulsifying with stirring. there is.

The composition of the present invention has a glossy texture and excellent detergency originally possessed by oil-in-water emulsions, and exhibits a unique effect of improving ultraviolet ray protection upon contact with water. It is particularly suitable.

The water-in-water emulsified sunscreen cosmetic of the present invention can be provided as, for example, sunscreen cream, sunscreen lotion, sunscreen lotion, and can also be used as a foundation with sunscreen effect, makeup base, makeup cosmetics, hair cosmetics, etc. can

Example

The present invention will be described more specifically by way of examples below, but the present invention is not limited thereto. In addition, unless otherwise indicated, the compounding amount shows the mass % with respect to the whole amount.

(Example and comparative example)

The oil-in-water emulsified sunscreen cosmetics shown in Examples and Comparative Examples were prepared by adding an oil phase in which separately heated and dissolved oil-based components were added to an aqueous phase in which aqueous components were heated and dissolved as necessary, and emulsified by stirring.

Measurement of UV protection effect

The cosmetics (sample) in each case were dropped in an amount of 2 mg/cm2 on a measurement plate (S plate) (5 × 5 cm V-groove PMMA plate, SPF MASTER-PA01), applied with fingers for 60 seconds, dried for 15 minutes, and then , and the absorbance was measured with a U-3500 magnetic green spectrophotometer manufactured by Hitachi, Ltd. Glycerin without ultraviolet absorption was used as a control, and the absorbance (Abs) was calculated by the following formula.

Abs=-log(T/To)

T: transmittance of sample, To: transmittance of glycerin

The measured plate was sufficiently immersed in water having a hardness of 50 to 500, and stirred in water as it was for 30 minutes (300 rpm with a 3-1 motor). After that, it was dried for about 15 to 30 minutes until the water droplets on the surface disappeared, and the absorbance was measured again, and the Abs change rate (the following formula) was calculated as the effect of improving the ultraviolet protection ability from the integrated value of the absorbance (Abs) before and after the water bath. .

Effects of improving UV protection:

Abs change rate (%) = (integrated value of Abs after bathing) / (integrated value of Abs before bathing) × 100

In the present invention, when the Abs change rate exceeds 100 (%), it is defined as an improvement in the UV protection effect.

(Examples 1 and 2 and Comparative Examples 1 to 5)

Cosmetics having the compositions listed in Table 1 below were adjusted, and the Abs integrated values before and after water bathing and their change rates were determined.

As shown in Table 1, even if the blending amount of (A) sunscreen agent and (B) fatty acid is the same, when the neutralization rate of (B) fatty acid exceeds 51% (Comparative Examples 1 to 5), the sunscreen effect after bathing has been lowered On the other hand, when the neutralization rate of (B) fatty acids was 51% or less (Examples 1 and 2), the UV protection effect after bathing increased by about 24% compared to before bathing.

(Examples 3 and 4)

Cosmetics having the compositions listed in Table 2 below were adjusted, and the integrated Abs value before and after bathing and the rate of change thereof were determined.

As shown in Table 2, compared to the case of including only component (A) and component (B) (Example 1), (C) when an oil component having an IOB of 0.5 or more is further included (Examples 3 to 4) In addition to the significant improvement in the UV protection effect before and after bathing, the improvement in the UV protection effect before and after the water bath (Abs change rate) was also significantly increased.

(Examples 5 to 15, Comparative Example 6)

Cosmetics having the compositions listed in Tables 3 and 4 below were adjusted, and the Abs integrated value before and after water bathing and its change rate were determined.

As shown in Tables 3 and 4, even if the type and amount of fatty acids or the combination of other ingredients are changed, as long as the requirements set forth in claim 1 are satisfied, the UV protection effect after bathing is improved for any cosmetic compared to before bathing. The effect peculiar to the present invention was obtained. However, in Comparative Example 6 in which the compounding ratio of the "ultraviolet sunscreen agent" and the "fatty acid" was 10.0, the effect peculiar to the present invention in that the ultraviolet protection effect was improved after bathing in water was not obtained.

(Examples 16 to 23)

The cosmetics having the compositions listed in Table 5 below were adjusted, and the absorbance change rate before and after the water bath was determined when the water bath time was 30 seconds, 1 minute, or 5 minutes. The results are shown in Table 5.

As is evident from the results shown in Table 5, in Example 16 in which the IOB did not contain an oil component of 0.5 or more, Example 17 in which the IOB contained an oil component of 0.5 or more at 0.1% by mass relative to the change rate exceeding 100% after being bathed in water for 5 minutes. In , the change rate exceeded 100% with a 1-minute water bath. Moreover, in Examples 18 to 23 in which the blending amount of the oil component having an IOB of 0.5 or more was 1% by mass and 5% by mass, the change rate exceeded 100% in a water bath of only 30 seconds. That is, it was confirmed that the rate of expression of the effect of improving the UV protection ability by water bathing increased by adding an oil component having an IOB of 0.5 or more.

(Example 24, 25)

Cosmetics having the compositions listed in Table 6 below were prepared, and the absorbance change rate before and after the water bath was determined when the water bath time was 30 minutes. The results are shown in Table 6.

As shown in Table 6, even if the type or compounding amount of the sunscreen agent (component (A)) is changed, as long as the requirements of the present invention are satisfied, any cosmetic is unique to the present invention in that the ultraviolet protection effect is improved after bathing compared to before bathing. effect was obtained.

Fig. 1 shows micrographs of cross-sections of the cosmetic coating film immediately after the cosmetic composition of Example 19 was applied to a simulated skin substrate (PMMA substrate with irregularities) and after bathing in water for 30 minutes. In the cross section of the coating film immediately after application to the skin ridge ((a) and (b)) and immediately after application to the skin groove ((c)), the thickness of the coating film is uneven due to large unevenness of the film, but after 30 minutes of water bath (skin ridge : (d) and (e); skin groove: (f)), it can be confirmed that the coating film is dense and uniform.

Other formulation examples (Examples 26 to 28) of the cosmetic of the present invention are shown below. Also in the cosmetics described in the formulation examples below, an effect peculiar to the present invention was observed that the ultraviolet protection effect was improved after bathing compared to before bathing.

Example 26: Sunscreen Cream

Example 27: UV protection lotion

Example 28: UV protection lotion

Claims (6)

(A) a UV protection agent;
(B) a fatty acid that is solid at room temperature, and
(C) contains an oil component having an IOB of 0.5 or more selected from ester oils, polyalkylene glycols, and alkylene oxide derivatives represented by the following formula (I);
The neutralization rate of the fatty acid is 51% or less,
An oil-in-water emulsified sunscreen cosmetic in which the compounding mass ratio ((A)/(B)) of (A) a sunscreen agent and (B) a solid fatty acid at room temperature is within the range of 0.1 or more and less than 10.0.
R ¹ O-[(AO) _m (EO) _n ]-R ² (I)
[Wherein, AO is an oxyalkylene group having 3 to 4 carbon atoms, EO is an oxyethylene group, m and n are the average number of added moles of the oxyalkylene group and the oxyethylene group, respectively, and 1≤m≤70, 1≤ n≤70, and R ¹ and R ² are the same or different hydrocarbon groups having 1 to 4 carbon atoms or hydrogen atoms.] delete According to claim 1,
A cosmetic composition wherein the (C)oil having an IOB of 0.5 or more is one or two or more selected from alkylene oxide derivatives. According to claim 1,
(C) Cosmetics in which the oil component having an IOB of 0.5 or more is one or two or more selected from polyoxyethylene/polyoxypropylene dimethyl ether and polyalkylene glycol. According to claim 1,
The (C) oil having an IOB of 0.5 or more contains polyoxyethylene (14) polyoxypropylene (7) dimethyl ether and/or polyethylene glycol and/or polypropylene glycol and/or polyoxybutylene polyoxypropylene glycol. cosmetics. The method of any one of claims 1 and 3 to 5,
Cosmetics wherein the (B) fatty acid is one or two or more linear fatty acids selected from stearic acid, palmitic acid, myristic acid and behenic acid.

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